Yesterday I was able to login on 1.2.11, I cannot anymore now.
I've upgraded yesterday cacti & spine from 1.2.7 to 1.2.11. I was not able to install cacti with templates, stuck on 42% twice, so deselected them. Pre-requisite checks were all fine.
I did restart apache2, did a reboot, tried different browser, in privacy mode too. I'm glad I have snapshots.. Nothing related in cacti.log or cacti_stderr.log.